Biologicals
You may need a U.S. Department of Agriculture permit and/or a Centers for Disease Control and Prevention permit to import biological specimens including bacterial cultures, culture medium, excretions, fungi, arthropods, mollusks, tissues of livestock, birds, plants, viruses, or vectors for research, biological or pharmaceutical use. Permit requirements are located under æ’¤ermits on the USDA Web site and CDC permit information can be found on the Etiologic Agent Import Permit Program page. ( APHIS - Permits ) ( Etiologic Agent Import Permit Program )

Fish and Wildlife
Certain fish and wildlife, and products made from them, are subject to import and export restrictions, prohibitions, permits or certificates, as well as requirements. CBP recommends that you contact the U.S. Fish and Wildlife Service before you depart if you plan to import or export any of the following:

Wild birds, land or marine mammals, reptiles, fish, shellfish, mollusks or invertebrates;
Any part or product of the above, such as skins, tusks, bone, feathers, or eggs; or
Products or articles manufactured from wildlife or fish.
Endangered wildlife species, and products made from them, generally may not be imported or exported. You will need a permit from the FWS to import virtually all types of ivory, unless it is from a warthog. The FWS has many restrictions and prohibitions on various kinds of ivory - Asian elephant, African elephant, whale, rhinoceros, seal, pre-Endangered Species Act, post-CITES (Convention on International Trade in Endangered Species) and many others - and urge you to contact them before you acquire ivory in a foreign country. You may contact the Management Authority at 1-800-358-2104. Pressing Option 3 will provide you with general information, and Option 4 will connect you to the permits section. You can also get information on permits. ( U.S. Fish and Wildlife Service - Permits )

You may import an object made of ivory if it is an antique. To be an antique the ivory must be at least 100 years old. You will need documentation that authenticates the age of the ivory. You may import other antiques containing wildlife parts with the same condition, but they must be accompanied by documentation proving they are at least 100 years old. Certain other requirements for antiques may apply.

If you plan to buy such things as tortoiseshell jewelry, or articles made from whalebone, ivory, skins or fur, contact the:

U.S. Fish and Wildlife Service
Division of Law Enforcement
P.O. Box 3247
Arlington, VA 22203-3247

You can also call 1-800-358-2104 or visit the U.S. Fish and Wildlife Service Web site. ( U.S. Fish and Wildlife Service ) Hunters can get information on the limitations for importing and exporting migratory game birds from this office as well or from the Migratory Birds page. ( Migratory Birds )

The U.S. Fish and Wildlife Service has designated specific ports of entry to handle fish and wildlife entries. If you plan to import anything discussed in this section, please contact CBP about designated ports and the brochure Pets and Wildlife, which describes the regulations CBP enforces for all agencies that oversee the importation of animals.

Some states have fish and wildlife laws and regulations that are stricter than federal laws and regulations. If you are returning to such a state, be aware that the stricter state laws and regulations have priority. Similarly, the federal government does not allow you to import wild animals into the United States that were taken, killed, sold, possessed or exported from another country if any of these acts violated foreign laws.

Game and Hunting Trophies
Information on bringing back your game or hunting trophy can be found at the U.S. Fish and Wildlife Service's Information on Hunting and Fishing page. ( Information on Hunting and Fishing ) Currently, 14 ports of entry are designated to handle game and trophies; other ports must get approval from the U.S. Fish and Wildlife Service to clear your entry.

Depending on the species you bring back, you might need a permit from the country where the animal was harvested. Regardless of the species, you are required to fill out a Fish and Wildlife Form 3-177, Declaration for Importation or Exportation. ( USFWS Form 3-177 )

Trophies may also be subject to inspection by CBP for sanitary purposes. General guidelines for importing trophies can be found on under the APHIS Import Authorization System (IAS) on the Guidelines for the Importation of Ruminant, Swine, and Bird Trophies page, or by writing to:

You can also call (301) 734-3277. ( Guidelines for the Importation of Ruminant, Swine, and Bird Trophies )

Nonhuman primate trophy materials may require a permit from the Centers for Disease Control and Prevention. Prospective importers of nonhuman primate trophy materials from nonhuman primates should review the permit requirements and complete an application form, following the Guidance for Individuals Wishing to Import Non-Human Primate Trophies, Skins or Skulls. ( Guidance for Individuals Wishing to Import Non-Human Primate Trophies, Skins or Skulls ) Trophy materials of other animals under import embargo because of viral zoonotic infections, such as civets, Asian birds, and African rodents, may be imported if the body has been sufficiently processed to render it non-infectious. Proper methods of accomplishing this include:

Heating to an internal temperature of 70 degrees Celsius (158 degrees Fahrenheit) or placing in boiling water for a minimum of 30 minutes);
Preservation in 2 percent formaldehyde;
Chemically treating in acidic or alkaline solutions (soaking in a solution below pH 3.0 or above pH 11.5 for 24 hours); or
The use of hypertonic salts.
Also, federal regulations do not allow the importation of any species into a state with fish or wildlife laws that are more restrictive than federal laws. If foreign laws were violated in the taking, sale, possession or export to the United States of wild animals, those animals will not be allowed entry into the United States.

Warning: There are many regulations, enforced by various agencies, governing the importation of animals and animal parts. Failure to comply with them could result in time-consuming delays in clearing your trophy through CBP. You should always call for guidance before you depart.

A Legend in my own mind!"one hundred grains in the right place is worth a thousand in the wrong." Captain Brocklehurst

I guess I would go with what brick posted. I got lucky ( ignorance is bliss ) or like I said ( Lucky ) I came back with several wooden articles and some tapestries from Zambia and Botswana (masks' and a native drum set for my son) and never got stopped through customs in any country.

I have never had to pay customs for anything brought back either. Rarely even have to open my gun case but more so now than in the past when they didnt even bother. Now mostly they want to see your customs form and they ask if it matches your gun, you say yes without hesitation and they wave you thru.